Clarify what is expected of the user after they are provided YAML in "Create Service" workflow

[datho7561]

It's not apparent what is expected of the user if they use the "Create Service" workflow and are presented with the YAML.

They are expected to apply this YAML to the cluster, either through the "Create" CodeLens, the "OpenShift: Create" command, or using the cli (kubectl create -f FILENAME).

It would be nice to explain this to the user, either in the notification popup when they are presented with the YAML, or maybe in a new step in the wizard before they are presented with the YAML.

See discussion in #3508 (review)